检索结果-南通市图书馆

NUMERICAL SIMULATION OF COLUMNAR TO EQUIAXED TRANSITION FOR DIRECTIONALLY SOLIDIFIED Ti-44Al ALLOY

在线全文

学校读者我要写书评

暂无评论

Acta Metallurgica Sinica(English Letters) 2008年第2期21卷 146-156页

作者： K.F. Wang J.J. Guo G.F. Mi C. Y. Li h.z. fu School of IVlaterials Science and Engineering Henan Polytechnic University Jiaozuo 454100 China School of Materials Science and Engineering Harbin Institute of Technology Harbin 150001 China

Solute diffusion controlled solidification model was applied to simulate the columnar to equiaxed transition （CET） during directional solidification of Ti-44Al alloy. The simulation results show that the solutal interactions from growing equiaxed grains play an important role on CET. The effects of the applied thermal gradient and pulling velocity, the equiaxed seed spacing and nucleation undercooling on the CET are investigated in the present simulation. The simulated results indicated that the columnar branch spacing depends not only on the thermal gradient and the pulling velocity, but also on number of the seeds. A spacing adjustment can occur through initiation of seeds that develop into new columnar grains. The dependence of the CET on the thermal gradient and pulling velocity, qualitatively agrees with the analytical CET model of hunt,

关键词： Ti-44Al alloy Directional solidification columnar to equiaxedtransition (CET) Numerical simulation

Advancements and Challenges in Organic–Inorganic Composite Solid Electrolytes for All‑Solid‑State Lithium Batteries

在线全文

学校读者我要写书评

暂无评论

Nano-Micro Letters 2025年第1期17卷 46-97页

作者： Xueyan zhang Shichao Cheng Chuankai fu Geping Yin Liguang Wang Yongmin Wu hua huo State Key Laboratory of Space Power‑Sources School of Chemistry and Chemical EngineeringHarbin Institute of TechnologyHarbin 150001People’s Republic of China College of Chemical and Biological Engineering Zhejiang UniversityHangzhou 310058People’s Republic of China State Key Laboratory of Space Power-Sources 2965 Dongchuan RoadMinhang DistrictShanghai 200240People’s Republic of China

To address the limitations of contemporary lithium-ion batteries,particularly their low energy density and safety concerns,all-solid-state lithium batteries equipped with solid-state electrolytes have been identified as an up-and-coming *** the various SEs,organic–inorganic composite solid electrolytes(OICSEs)that combine the advantages of both polymer and inorganic materials demonstrate promising potential for large-scale ***,OICSEs still face many challenges in practical applications,such as low ionic conductivity and poor interfacial stability,which severely limit their *** review provides a comprehensive overview of recent research advancements in ***,the influence of inorganic fillers on the main functional parameters of OICSEs,including ionic conductivity,Li+transfer number,mechanical strength,electrochemical stability,electronic conductivity,and thermal stability are systematically *** lithium-ion conduction mechanism of OICSE is thoroughly analyzed and concluded from the microscopic ***,the classic inorganic filler types,including both inert and active fillers,are categorized with special emphasis on the relationship between inorganic filler structure design and the electrochemical performance of ***,the advanced characterization techniques relevant to OICSEs are summarized,and the challenges and perspectives on the future development of OICSEs are also highlighted for constructing superior ASSLBs.

关键词： Composite solid electrolytes Inorganic filler Interfacial stability Li-ion conduction mechanism Characterization techniques

EFFECT OF ANNEALING ON DAMPING CAPACITIES OF AS-CAST zA27 ALLOY

在线全文

学校读者我要写书评

暂无评论

Acta Metallurgica Sinica(English Letters) 2006年第5期19卷 379-384页

作者： z.M. zhang J. C. Wang h.z. Liu X.F. Guo School of Materials Science ＆ Engineering Xi＇an University of TechnologyXi＇an 710048 China State Key Laboratory of Solidification Processing Northwestern PolytechnicalUniversity Xi＇an 710072 China

zA27 alloy was prepared by casting with permanent mold and then annealed at 250℃ for 1-4h. The damping capaciG of the alloy was measured using a testing apparatus based on the cantilever beam technique. It was found that the as-cast zA27 alloy possesses high damping capacity with the value of 1.3 × 10^4 at 320hz. After annealed at 250℃ for lh, the damping capacity decreases to 1.1 × 10^-3 and then remains constant even when the annealing time is increased to 4h. The microstructure of the as-cast zA27 alloy consists of large dendrites of Al-rich PrimaG （x-phases, eutectoid （α ＋ η） and nonequilibrium eutectic phases （α ＋ η ＋ ε）. After annealing at 250℃ for lh, the e phase disappears due to dissolution into the matrix, and the spacing between the flakes of eutectoid increases. The further increase in the annealing time has little effect on the spacing. The damping mechanism of the alloy was discussed considering the thermoelastic damping and defect damping. The value of thermoelastic damping accounts only for 7%-8% in the overall damping in cantilever beam damping measurements and the damping capacity of the zA27 alloy came mainly from defect damping.

关键词： damping capacity zA27 alloy annealing

DAMPING BEhAVIOR OF ULTRAFINE-GRAINED PURE ALUMINUM L2 AND ThE DAMPING MEChANISM

在线全文

学校读者我要写书评

暂无评论

Acta Metallurgica Sinica(English Letters) 2006年第3期19卷 223-227页

作者： z.M. zhang C.J. Xu J.C. Wang h.z. Liu School of Materials Science ＆ Engineering Xi＇an University of Technology Xi＇an 710048 Ghina State Key Laboratory of Solidification Processing Northwestern Polytechnical University Xi＇an 710072 Ghina

Ultrafine-grained pure aluminum L2 with a mean grain size of 1.01μm was produced by equal channel angular pressing （ECAP） and annealing at 150℃ for 2h. Damping behavior of the alloy was measured using a dynamic mechanical thermal analyzer. The alloy had an excellent damping capacity Q^-1 with the ambient value being 9.8×10^-3 at 1.0hz when the strain amplitude was 2.0×10^-5. The damping behavior of the alloy showed a non-linear damping variation tendency, that is, with an increase in temperature and a decrease of frequency, the damping capacity of the alloy increased. The damping capacity increased with the strain amplitude when the strain amplitude was less than 4.6×10^-5. When the strain amplitude was higher than 4.6×10^-5, the damping capacity became a constant and independent of strain amplitude. The high damping capacity was attributed to dislocation unpinning and a drag of dislocation on pinning points.

关键词： ECAP ultrafine grain damping capacity aluminum alloy

NUMERICAL SIMULATION OF PARTICLE SEPARATION IN AN OIL-SAND SEPARATOR

在线全文

学校读者我要写书评

暂无评论

Journal of hydrodynamics 2001年第1期13卷 81-85页

作者： Wei, X.L. Tian, W.D. Wang, J.M. Sheng, h.z. Inst. of Mechanics Chinese Acad. of Sci. Beijing 100080 China

The gathering systems of crude oil are greatly endangered by the fine sand and soil in oil. Up to now, how to separate sand from the viscid oil is still a technical problem for oil production at home or abroad. Recently, Institute of Mechanics in Chinese Academy of Sciences has developed a new type of oil-sand separator, which has been applied successfully in oil field in situ. In this paper, the numerical method of vortex-stream function is used to predict the liquid-solid separating course and the efficiency for this oil-sand separator. Results show that the viscosity and particle diameter have much influence on the particle motion. The calculating separating efficiency is compared with that of experiment and indicates that this method can be used to model the complex two-phase flow in the separator.

关键词： Computer simulation Crude petroleum Petroleum engineering Separators

RESEARCh ON LASER DIRECT DEPOSITION PROCESS OF Ti-6Al-4V ALLOY

在线全文

学校读者我要写书评

暂无评论

Acta Metallurgica Sinica(English Letters) 2007年第3期20卷 171-180页

作者： S.Y. Gao Y.z. zhang L.K. Shi B.L. Du M.z. Xi h.z. Ji Mechanical Engineering College Yanshan University O~mhuangdao 066004 China Beijing General Research Institute for Nonferrous Metals Beijing 100088 China

Laser direct deposition （LDD） of metallic components is an advanced technology of combining CAD/CAM （computer aided design/computer aided manufacturing）, high power laser, and rapid prototyping. This technology uses laser beam to melt the powders fed coaxiaUy into the molten pool by the laser beam to fabricate fuUy dense metallic components. The present article mainly studies the LDD of Ti-6Al-4V alloy, which can be used to fabricate aircraft components. The mechanical properties of the Ti-6Al-4V alloy, fabricated by LDD, are obtained using the tension test, and the oxygen content of used powders and deposited specimens are measured. In the present article, it can be seen that the mechanical properties obtained using this method are higher than the ones obtained by casting, and equal to those got by wrought anneal. One aircraft part has been made using the LDD process. Because of this aircraft part, with sophisticated shape, the effect of the laser scanning track on the internal soundness of the deposited part was discussed.

关键词： laser direct deposition Ti-6Al-4V alloy mechanical property depositing process aircraft component

Endoplasmic reticulum stress and autophagy in cerebral ischemia/reperfusion injury:PERK as a potential target for intervention

在线全文

学校读者我要写书评

暂无评论

Neural Regeneration Research 2025年第5期20卷 1455-1466页

作者： Ju zheng Yixin Li Ting zhang Yanlin fu Peiyan Long Xiao Gao zhengwei Wang zh.z.ong Guan Xiaolan Qi Wei hong Yan Xiao Key Laboratory of Endemic and Ethnic Diseases Ministry of Education&Key Laboratory of Medical Molecular Biology of Guizhou ProvinceGuizhou Medical UniversityGuiyangGuizhou ProvinceChina Guizhou Center for Disease Control and Prevention GuiyangGuizhou ProvinceChina Department of histology and Embryology Guizhou Medical UniversityGuiyangGuizhou ProvinceChina Collaborative Innovation Center for Prevention and Control of Endemic and Ethnic Regional Diseases Co-constructed by the Province and Ministry GuiyangGuizhou ProvinceChina

Several studies have shown that activation of unfolded protein response and endoplasmic reticulum(ER)stress plays a crucial role in severe cerebral ischemia/reperfusion *** occurs within hours after cerebral ischemia,but the relationship between ER stress and autophagy remains *** this study,we established experimental models using oxygen-glucose deprivation/reoxygenation in PC12 cells and primary neurons to simulate cerebral ischemia/reperfusion *** found that prolongation of oxygen-glucose deprivation activated the ER stress pathway protein kinase-like endoplasmic reticulum kinase(PERK)/eukaryotic translation initiation factor 2 subunit alpha(e IF2α)-activating transcription factor 4(ATF4)-C/EBP homologous protein(ChOP),increased neuronal apoptosis,and induced ***,inhibition of ER stress using inhibitors or by si RNA knockdown of the PERK gene significantly attenuated excessive autophagy and neuronal apoptosis,indicating an interaction between autophagy and ER stress and suggesting PERK as an essential target for regulating *** autophagy with chloroquine exacerbated ER stress-induced apoptosis,indicating that normal levels of autophagy play a protective role in neuronal injury following cerebral ischemia/reperfusion *** from this study indicate that cerebral ischemia/reperfusion injury can trigger neuronal ER stress and promote autophagy,and suggest that PERK is a possible target for inhibiting excessive autophagy in cerebral ischemia/reperfusion injury.

关键词： apoptosis ATF4 autophagy C/EBP homologous protein cerebral ischemia/reperfusion injury eIF2α endoplasmic reticulum stress PERK

EFFECTS OF zn CONCENTRATION ON WETTABILITY OF Sn-zn ALLOY ON Cu AND ON ThE INTERFACIAL MICROSTRUCTURE BETWEEN Sn-zn ALLOY AND Cu

在线全文

学校读者我要写书评

暂无评论

Acta Metallurgica Sinica(English Letters) 2006年第4期19卷 251-257页

作者： h.z. huang X.Q. Wei L. zhou X.D. Liu G.L. Guo School of Materials Science and Engineering Nanchang University Nanchang 330047 China East China Institute of Technology Fuzhou 344000 China

The potential of using a hypoeutectic, instead of eutectic, Sn-zn alloy as a lead-free solder has been discussed. The nonequilibrium melting behaviors of a series of Sn-zn alloys were examined by differential thermal analysis. It was found that at a heating rate of 5℃/min, *** exhibited no melting range. Dipping and spreading tests were carried out to characterize the wettability of Sn-zn alloys on Cu. Both tests exhibited that Sn-6.5zn has significantly better wettability on Cu than Sn-9zn. The reaction layers formed during the spreading tests were examined. When the zn concentration fell between 2.5wt%-9wt%, two reaction layers were formed at the interface, a thick and flat Cu5zn8 adjacent to Cu and a thin and irregular Cu-zn-Sn layer adjacent to the alloy. Only a Cu0Sn5 layer was formed when the zn concentration decreased to 0.5wt%. The total thickness of the reaction layer（s） between the alloy and Cu was found to increase linearly with the zn concentration.

关键词： lead-free solder Sn-zn alloy wettability interface intermetallic compound

TEMPORAL EIGENVALUE SPECTRA OF BOUNDARY-LAYER FLOW OVER RIGID WALL AND COMPLIANT WALL

在线全文

学校读者我要写书评

暂无评论

Journal of hydrodynamics 2001年第1期13卷 70-74页

作者： zhao, h.z. Yeo, K.S. Dep. of Mechanics Huazhong Univ. of Sci. and Technol. Wuhan 430074 China

The temporal eigenvalue spectra of the equation system for the boundary-layer flows over both rigid wall compliant and viscoelastic compliant wall are numerically studied. In a rigid-wall case only the fluid-based eigenmodes, the Tollmien-Schlichting instability (TSI) mode, exist. In a compliant-wall case, both the TSI and wall-based compliance-induced instability flow instability (CIFI) modes occur. The variations of the two categories of eigenvalues at various wall material stiffness and damping are also displayed.

关键词： Computer simulation Eigenvalues and eigenfunctions Stability